NASA's Mercury orbiter, Messenger, is going out with a bang as it prepares to dive bomb the planet in glorious fashion, leaving behind a new crater on the planet closest to the sun that will measure approximately 16 meters wide once the dust has settled.
NASA's Messenger craft has already made history, being the first spacecraft to circle Mercury and it is expected to slip out of orbit and into history on Thursday as it slams into the surface following a four year tour of the rocky planet. The spacecraft will be travelling 14,081 kilometers per hour or 8,750 miles per hour when it slams into the surface, a speed that is fast enough to carve out a crater that is 16 meters or 52 feet wide. The spacecraft itself measures about 3 meters wide or 10 feet from solar wingtip to wingtip.
Messenger has already run out of fuel, but ground controllers managed some fancy maneuvers to get just a little more life out of the craft by raising Messenger's orbit by dipping into the helium gas reserves not originally intended for use as fuel. Now, all that has been exhausted as well and Messenger is now at the mercy of Mercury's gravity.
"I guess the end is coming," the Messenger team said via Twitter earlier this week. "After 10 years, spacecraft will end life as just another crater on Mercury's surface."
During its four years orbiting the planet, Messenger made more than 4,000 laps around it and discovered volcanic deposits that are helping to explain the planet's eruptive and interior melting past with polar caps of frozen water at or near the surface and incredible global shrinkage thanks to its cooling interior.
Messenger also found that Mercury contains many more volatile elements than originally expected, such as potassium and sulfur, surprising scientists given its close proximity to the Sun.
On Thursday, Messenger is expected to crash in to the side of Mercury facing away from Earth, so scientists will be unable to observe the impact. Scientists that are a part of the mission expect to continue to collect data about the little planet until about 10 to 15 minutes before its final, fatal plunge. The expected crash site, is about two-thirds of the way up the planet, near the north pole. Mercury is the smallest planet in our solar system measuring in at only slightly bigger than our moon.
This isn't the last mission to the planet closest to the Sun, a pair of European and Japanese spacecraft will aim for Mercury following a launch in 2017 from South America's French Guiana. It will take approximately seven years for the two satellites to reach the planet and enter orbit, in 2024.
